2004 Cadillac DeVille Owner's Manual - Page 182

This light tells you if there could be a problem with your engine oil pressure. Security Light For information regarding this light, see Theft-Deterrent Systems on page 2-20. The light goes on when you turn your key to ON or START. It goes off once you start your engine. That is a check to be sure the light works. If it does not come on, be sure to have it fixed so it will be there to warn you if something goes wrong. When the light comes on and stays on, it means that oil is not flowing through your engine properly. You could be low on oil and you might have some other system problem. Fog Lamp Light This light will come on when the fog lamps are in use. It will go out when the fog lamps are turned off. For more information about the fog lamps, see "Fog Lamps" under Exterior Lamps on page 3-16. 3-56